Development of caramel colour with improved colour stability and reduced 4-methylimidazole

ABSTRACT

This study investigated the effect of chemical substances, such as Mg²⁺ (as magnesium sulphate), Zn²⁺ (as zinc sulphate), Fe²⁺ (as iron sulphate), ascorbic acid, and citric acid, on the formation of 4-methylimidazole (4-MI) and colour stability of caramel colour. The 4-MI concentration in the caramel colour without chemical substances was 963.10 μg/g, and this decreased the most (67.7%) with the addition of 0.1 molar ratio of citric acid. Colour stability was evaluated by measuring the total colour change (ΔE) after storage, and heating in pH 2, 4, and 7 solutions and 50% solution in ethyl alcohol. Among the chemical substances added to reduce 4-MI in the caramel colour, Mg²⁺ (0.1 molar ratio) and ascorbic acid improved the colour stability more than the others.

GRAPHICAL ABSTRACT

KEYWORDS:

• 4-Methylimidazole
• chemical substances
• organic acid
• caramel colour
• colour stability

Additional information

Funding

This research was supported by the Agriculture, Food and Rural Affairs Research Centre Support Program, and Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries [IPET 118012031SB010] through the Ministry of Agriculture, Food and Rural Affairs; and the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (grant number NRF-2018R1A2B6002634), Republic of Korea.